Piaggio 674594 Automatic Vacuum Fuel Tap – Vespa, Liberty, Fly, Zip, Typhoon, Aprilia and Gilera

This is the original automatic vacuum fuel tap from the Piaggio Group, part number 674594. It mounts on the fuel tank and opens the fuel flow only when the engine is running: the manifold vacuum pulls the diaphragm and the tap opens automatically, without levers to turn. When the engine is off, it closes, so fuel doesn't flow into the carburetor. It comes complete with a fuel strainer with mesh filter and an O-ring gasket.

✓ Strengths

• Genuine Piaggio spare part, not a cross-referenced equivalent.
• Direct fit: fittings, threads, and fuel strainer are as specified by the manufacturer.
• Die-cast metal body, not plastic.
• Includes fuel strainer with mesh filter and O-ring gasket: no separate parts needed.
• Automatic shut-off when the engine is off: no fuel flowing into the carburetor.
• Covers a very wide range of Vespa, Liberty, Fly, Zip, Typhoon, Skipper, Aprilia SR, and Gilera DNA models.

Technical Specifications

Vehicle Compatibility

The list is taken from the official Piaggio spare parts catalog (B2B area). If you are unsure about your version, send us the chassis number and we will verify it before shipping.

Who It's Perfect For

For those whose scooter stalls while riding or won't start anymore, and have already ruled out spark plug and filter issues. For those who find fuel in the crankcase or air filter because the fuel tap no longer closes when the engine is off. And for mechanics who want to install the original part instead of an adapted universal one: here, the connections, fuel strainer, and O-ring are already correct, just install and go.

Frequently Asked Questions

How does a vacuum fuel tap work?
It has a diaphragm connected by a small hose to the intake manifold. When the engine runs, it creates a vacuum, the diaphragm moves, and opens the fuel flow. As soon as you turn it off, the vacuum disappears, and the tap closes automatically. That's why there's no lever to turn.

What exactly do I receive?
The complete fuel tap with its fuel strainer — the long tube that goes down into the tank, with the mesh filter at the bottom — and the O-ring seal. It's the assembly as specified by the manufacturer, not just the tap body.

How do I know it needs to be replaced?
The typical symptoms are three: the engine starts and then stalls shortly after as if it's running out of fuel; the vehicle no longer starts when cold even with a new spark plug; or you find fuel where it shouldn't be, because the tap continues to let fuel pass when the engine is off. A mesh filter clogged with tank sediment also produces the same effect.

Is it suitable for fuel-injected models?
No. This fuel tap belongs to carburetor systems. Fuel-injected generations — for example, Liberty and Vespa i-Get from 2015 onwards — have a different system, with a fuel pump in the tank, and use different part numbers.

Do I need anything else for installation?
Normally no: the O-ring gasket is included. However, it's worth checking the vacuum hose and the fuel hose: if they are hardened or cracked, it's advisable to replace them at the same time, as they are the most common cause of a "new tap that doesn't open."

Is it genuine or an equivalent?
It is the genuine spare part from the Piaggio Group, identified by the factory code 674594 and listed in the fuel tank diagram in the catalog. It is not an adapted universal tap. Moon Bike S.r.l. is an authorized dealer and ships with an invoice and manufacturer's warranty.